Forming packing ring stock



sept.v s, 1936.

w. DAvvlEs FORMING PACKING RINGSTOCKv Filed April 8, 1935 Sept. 8, 1936.W DAVlES 2,053,363

FORMING PACKING RING STOCK Filed April 8, 1955 3 Sheets-Sheet 2 YON.. YY Y Y NN Y WN YQN CNY.

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FORMING PACKING RING STOCK Filed April 8, 1955 3 Sheets-Sheet 3 Fig il20 ,22'

Inf/@afar Wayne ,Daf/vies Patented Sept. 8, 1936 UNITED STATES PATENTOFFICE FORMING PACKING RING STOCK Wayne Davies, Evanston, Ill.

Application April 8, 1935, Serial No. 15,353

7 Claims.

This invention relates to the manufacture of packing rings of the typewhich are generally made of leather and U-form in cross section, andused for effecting a seal between a relatively moving plunger or pistonand a cylinder.

It is customary in forming such packings to use ring-shaped forged steeldies for operating upon previously cut flat leather rings for shapingthe leather into U-cross section. Such method of forming the packlngsrequires a large stock of forming rings according to the standard sizesrequired, and often the necessity of making the forming rings speciallyfor particular jobs.

This customary method of forming packing rings, or U-packings as calledin the trade, also limits the design of packings which may bepractically made by such method. When the leather rings thereof aredrawn in a. set of three steel rings the variation in leather substance,as well 20 as friction, causes the stock being formed to crawl on thedies unevenly, making any special design in section thickness ormaterial impossible, also causing excess waste in stock provided toallow for the slide in the dies, or crawl. Also the bre stresses andstrains set up in the U section or L section by the present method tendto thin the section at the point of bending on the ring corner,weakening the packing and extruding the wax or ller.

The purposes of the present invention are to overcome such limitationsin the forming process and to provide a machine which has the capacityof forming leather to the desired cross section for various types ofpacking from previously prepared strips of leather or other fibrous orfabric stock of great length, and to wind the formed strips while hotand the wax ller therein is soft into helices of suitable length so thatportions may be cut therefrom to Yform rings of any desired di- 40ameter and having lapped joints.

Other purposes of the invention are: to make unnecessary some of theoperations and to avoid the difficulties in bringing about a fairlyperfect production by the old method of forming the 45 packings by useof ring-shaped dies. For example, with the improved method and machinefor shaping the leather for use as packing, it is not necessary to soakthe stock in water before formlng and thus necessitate drying andshrinkage 50 after forming.

The improved method also reduces waste and avoids the need of trimmingand beveling theV edges of the packing after it is formed. This ma#chine also protects the leather from undue strains in the formingoperation and the use of a flexible core spacer is serviceable inprotecting the stock against distortion and assures uniformity in thenal product.

It is also possible with this machine to have the packing reinforcedwhere needed and to produce U, L or. V-shaped packings varying in crosssection as best suited for the work to be performed thereby.

Another advantage in forming packings according to this invention is theapplication of lengthwise tension, pressure and heat in forming leather,after it is loaded with wax and this insures complete wax impregnationof the leather, uniformity of wax density and results in a packinghaving longer life than that which is wax treated and trimmed afterforming.

The objects of the invention are accomplished by the use of a: machinesuch as illustrated in the drawings, wherein Figure 1 shows the formingand winding machine in side elevation.

Fig. 2 is a plan View of the machine with the winding mandrel partlybroken away.

Fig. 3 illustrates in cross sections a few types of packings made bythis machine.

Fig. 3A is a sectional view of a strip of packing material before it isbent to U-form by the forming rollers.

Fig. 4 is an enlarged fragmentary plan detail and partly in sectionshowing a series of forming rollers and a winding head.Y

Fig. 5 is a perspective view of the winding head.

Fig. 6 is a sectional detail taken on the line 6-6 of Fig. 4.

FigsfI, 8 and 9 are sectional details taken on the lines l, 8 and 9 ofFig. 4, and showing the kinds of-forming rollers which successivelyoperate upon the leather stock, as it passes through the machine.

Fig. l0 is an end view partly in section and broken away showing themandrel driving and supporting mechanism.

Fig. 1l shows one of the mandrel supports in side elevation, and amandrel in section resting thereon.

Fig. l2 is a sectional detail of the starting mandrel as indicated Vbythe line I2-I2 of Fig. 4.

Fig. 13 is an enlarged detail of a guide clamp and indicates the guidesin section.

Fig. 14 is a fragmentary sectional detail of the winding head to showthe helical ribs thereof engaging the heel of the U-packing strip.

The material operated upon, such as leather or other pliable fibrousmaterial, is in the form of leather belting, except that it may belaminated in -the table 5 edgewise.

such manner as to vary in lthickness from side to side according to thedesired ultimate cross-section of the packing. The leather or pliablestock is supplied to the machines in coils which are several hundredfeet in length, and these coils are placed in a drum-shaped receiver towhich steam is fed for the purpose of softening the leather by heatingthe wax or other fillers therein. From the drum the leather passessuccessively over forming rollers which gradually bend it up along theside edges in order to shape it into channel form. The temperature ofthe leather is maintained by electric heaters in the forming and windingmachine. The leather channel so formed is filled with a spacing strip offlexible material in order to prevent the flanges of the channel frombeing crowded inwardly when the material passes through the windinghead. The winding head is an internally threaded stationary heatedmember surrounding a rotating mandrel which receives the U-shaped stripof leather and draws it through the machine.

The threads on the stationary head cause the mandrel to wind the leatherinto a helix and the frictional engagement of the'leather with themandrel forces the mandrel in an axial direction according to the pitchof the thread. When one mandrel is filled, another mandrel is insertedso that the winding can continue on the second mandrel, etc. As eachmandrel is delivered from the machine with the leather packing woundthereon the wound strip of leather is clamped to the mandrel and severedso that the mandrel can be passed on for cooling.

With material so formed, U-shaped packing rings may be quickly providedof any desired diameter by uncoiling the required length of packingmaterial and cutting it to form a lapped joint. The beveled ends of thepacking are usually cemented together, and the ring is ironed to bringit to a perfectly true circular form.

In the drawings the drum-shaped receiver for the coils of leather isindicated at I, and is shown connected with a steam supply conduit 2.From the supply drum the leather strip L passes between the pulleys 3and 4, the latter serving to turn the strip of leather so that it willstart over A plurality of pairs of forming rollers 5 1, 8 9, and I|l IIgradually bend the leather into channel form. There are two pairs ofrollers 8 9 and I0 I I. When the stock leaves the last pair of rollersI0 II, it passes between the guide elements I2 and I3 and thetemperature is maintained by the heating elements I 4 and I5. The angesof the channelshaped strip of leather are held apart by a loose key I6,which irons the channel on the inside surfaces, but from that point onthe space between the flanges of the leather channel is filled by aexible spacer I1 which enters the guide formed by the members I2 and I3through a slot I8 and then passes along with the leather channel throughthe winding head I9 and around mandrels 20.

The flexible spacer strip I1 is of greater tensilel mandrel. Themandrels 20 may be hollow as indicated in Fig. l0, and have an end wall22 which has a central square perforation to receive a square shaft 23,and rotate with the shaft, while the mandrel is free to travellengthwise of its drive shaft. Shaft 23 is driven' through gearconnections 24 and 25 by motor 2E.

The mandrels are supported in cradles formed by belts 21, Fig. 1, whichare carried by pulleys 28 on the upper ends of standards 29.

'I'he stationary winding head I9 is made of two parts hinged together at30 and held together by the clamp 3l. Likewise the guide members I2 andI3 are connected by a hinge 32 and secured together by the clamps 33. Apart 34 of the guide, which is provided with the slot I8 for receivingthe spacer strip I1, is also hinged at 35 to the main part of the lowerguide. It is held in its operative guiding position by eccentric clamp35', Fig. 13, allowing adjustment of pressure through I6 to base ofU-leather section.

Also the pairs of forming rollers 6 to II inclusive are carried byseparable elements 36 and 31 as indicated in Fig. 2. 'I'hese membershinge at 38 and are drawn together by clamps 39; and are also adjustablethrough eccentrics in pivots below point 38 indicated by the leverhandles 43, Fig. 9.

The machine may thus be opened up for ease in starting a strip ofleather through it. When starting the end of the strip of leather isclamped to the first mandrel by tooth gripping element 40, Fig. 12. Thestrip is creased longitudinally where it is bent to angular or U-form bythe ridges 4I and 42 on the forming rollers, Figs. 1 and 8.

Figure 3 shows examples in cross sections of some of the possiblevariations in product, according to the use to which the packing is to.be put; for example, of the two forms marked A one shows a continuous Uwith an outside reinforced wear leg, and the other, of the samedlmensions, a continuous U with an inside reinforced wear leg. Either ofthese forms may be made without change in the dimensions of the flexiblespacer element I1, Fig. 4. The double wearing wall and the double heelor base reinforces the packing in a manner to lengthen its life.

FormfB may be used where the plunger wear is not excessive but where aheel reinforcement is necessary to prevent the packing from beingpinched at the heel.

Form C is used for extreme cases of plunger clearance and extremely highpressures, and form D is used where the heel must be rounded to fit thecurvature of the gland ring nose.

In the operation of this machine, the leather strips are treated withwax and have their edges beveled before these strips are acted upon bythe machine. After the forming operation further trimming or beveling isnot necessary. Thus the packing does not absorb water or oil at thebeveled edges as is the case where trimming is necessary after theforming operation.

The leather strips which are to be formed into U or other cross sectionsare carefully built up by laminations to vary the cross sectionaccording the the ultimate packing required and the edges of the stripwhich form the operating lips of the packings are beveled. The leatheris also wax treated before being operated upon by the machine. It comesto the machine wound flat in coils which are placed in the heating drumI to which steam is fed for the purpose of softening the wax and makingthe leather workable in the forming machine.

The forming rollers which are carried by hinged elements are swung apartto allow the strip to be drawn by hand through the forming part of themachine. The winding head is also opened and the end of the leatherstrip is attached to a mandrel 20 by means of the grip device 40, Fig.4. The winding head is then closed, guide members are closed, and theforming rollers are swung toward each other through their hingedsupports 36 and 3'I which are clamped together, adjusted to pressure byeccentric levers.

As the machine is started, the key I6, Fig. 4, is placed in position tohold separated the walls of the U-shaped leather strip L adjacent thepoint of entry of the spacing strip II. The mandrel 2U is rotatedthrough the square shaft 23 which is driven through the gearing 24 bymotor 26. This shaft passes through a square hole in the gear carriedthereon and may, therefore, be slid axially in its bearings to permitremoving or placing mandrels on the shaft. The mandrel driven by thisshaft may slide thereon during the winding operation. The leather iswound upon the mandrel in a helix according to the pitch of the threadon the internal surface of the xed winding head and incidentallyfrictionally grips and pushes the mandrel out along its drive shaft,bringing pressure against the heel of the channel on the outside settingthe angles.

By the method hereindescribed of forming packing ring stock, it ispossible to utilize strips of material with the edges thereof beveledprior to passing the material through forming elements which bring it tochannel form and also curve the stock into a helix of approximately theradius of the finished packing ring.

The beveled edges of the material operated upon are protected by aspacer strip which extends beyond the flanges of the channel-shapedpacking material. The spacer also holds the under leg of the channelsection against a mandrel and prevents the channel from opening. Thefixed helical rib of the winding head applies pressure on the base ofthe, channel-formed leather or brous stock and the convolutions of thehelical rib are so placed apart as not to contact with the beveled edgesof the material operated upon.

These edges are protected by the spacer I'I as illustrated in Fig. 14.

The guide members shown in Fig. 5 are horizontally adjustable forreceiving spacer strips I'l of different cross sections for completelyfilling the space within the channel or angle of the formed stock. Theslotted openings I8 are varied to suit the cross sections of the spacerstrips. The guide members serve to iron out the channeled stock andsmooth the angular edges thereof. The flexible spacer strip I'I ispressed against the under surface of the heel of the square basedchannel stock illustrated in the drawings. The guide members are formedto provide clearance for the beveled edges of the channeled stock.

The machine has capacity of forming strips of stock to the desired crosssection and one machine is usable for making several different styles ofpacking sections. The material operated upon is kept warm during theforming operation but is refrigerated to hold its form as it leaves thewinding head which causes the material to shrink and set firmly in theparticular sections and dimensions desired. The refrigeration may beeffected by circulating a cooling medium around the mandrels as theyleave the machine, as for example through the cooling coil 44, Fig. 4,in the member surrounding the mandrel and forming an extension of thewinding head.

I claim:

1. A machine for conditioning leather strips for use as packingsconsisting of a plurality of pairs of rollers'arranged for successiveoperation on the strip for bending the strip into substantially channelform, means for guiding a spacer into the channel formed strip as itleaves the rollers, and means for winding the channel formed strip withits spacer into a helix.

2. A machine of the class described comprising a plurality of pairs ofrollers arranged for forming fiat strips into channel form, means forguiding a spacer into the channel formed strip as it leaves saidrollers, winding mechanism for receiving the material with the. spacertherein and forming such material and spacer into a helix, said windingmechanism consisting of a stationary internally threaded cylinder, and arotating mandrel fitting within said cylinder, and means for guiding thematerial onto said mandrel into the space between the convolutions ofthe thread in said cylinder.

3. A machine of the class described comprising a plurality of pairs ofrollers arranged for forming flat strips into channel form, means forguiding a spacer into the channel formed strip as it leaves saidrollers, and winding mechanism for receiving the material with thespacer therein and forming such material and spacer into a helix, saidwinding mechanism consisting of a stationary internally threadedcylinder, a rotating mandrel fitting within said cylinder, means forguiding the mate.- rial onto said mandrel into the space between theconvolutions of the thread in said cylinder, and means for driving saidmandrel including a shaft longitudinally s lidable relative to saidmandrel.

4. A machine of the class described comprising means for drawing stripstock into channel form and applying heat during the drawing operation,a rotating mandrel for receiving the material and winding it into ahelix, a stationary winding head for guiding the material onto saidmandrel, said winding head being internally threaded and formed in twoparts which are hinged together.

5. A machine for forming fibrous stripstock into a channel comprising areceiver fora coil of said stock including means for applying heatthereto, two series of coacting rollers arranged to draw the strip stock,from said receiver and graduallyl change it into channel form, one ofsaid series of rollers being mounted for movement toward and away fromthe other series of rollers, a guide member for receiving the channelformed stock from said rollers and guiding a spacer strip between thelegs of the formed stock, and winding mechanism consisting of an elementhaving a fixed helical guide thread and a rotary member for drawing andironing out the channel formed stock between the convolutions of saidthread.

6. A machine for forming fibrous strip stock into a channel comprising areceiver for a coil of said stock including means for applying heatthereto, two series of coacting rollers arranged to draw the strip stockfrom said receiver and gradually change it into channel form, one ofsaid series of rollers being mounted for movement toward and away fromthe other series of rollers, a guide member for receiving the channelformed stock from said rollers and guiding a spacer strip between thelegs of the formed stock, and winding mechanism consisting of an elementhaving a fixed helical guide thread and a rotary member for drawing andironing out the channel formed stock between the convolutions of saidthread, and a heater for said winding mechanism.

'7. A machine of the class described comprising means for drawing stripstock into channel form and applying heat during the drawing operation,

a rotating mandrel for receiving the material and winding it into ahelix, a stationary winding head for guiding the material onto saidmandrel, and means for chilling and shrinking the stock Wound on saidmandrel.

WAYNE DAVIES.

